[PATCH] e1000e: fix cyclic resets at link up with active tx
From: Konstantin Khlebnikov <hidden>
Date: 2019-01-14 13:29:40
I'm seeing series of e1000e resets (sometimes endless) at system boot if something generates tx traffic at this time. In my case this is netconsole who sends message "e1000e 0000:02:00.0: Some CPU C-states have been disabled in order to enable jumbo frames" from e1000e itself. As result e1000_watchdog_task sees used tx buffer while carrier is off and start this reset cycle again. [ 17.794359] e1000e: eth1 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None [ 17.794714] IPv6: ADDRCONF(NETDEV_CHANGE): eth1: link becomes ready [ 22.936455] e1000e 0000:02:00.0 eth1: changing MTU from 1500 to 9000 [ 23.033336] e1000e 0000:02:00.0: Some CPU C-states have been disabled in order to enable jumbo frames [ 26.102364] e1000e: eth1 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None [ 27.174495] 8021q: 802.1Q VLAN Support v1.8 [ 27.174513] 8021q: adding VLAN 0 to HW filter on device eth1 [ 30.671724] cgroup: cgroup: disabling cgroup2 socket matching due to net_prio or net_cls activation [ 30.898564] netpoll: netconsole: local port 6666 [ 30.898566] netpoll: netconsole: local IPv6 address 2a02:6b8:0:80b:beae:c5ff:fe28:23f8 [ 30.898567] netpoll: netconsole: interface 'eth1' [ 30.898568] netpoll: netconsole: remote port 6666 [ 30.898568] netpoll: netconsole: remote IPv6 address 2a02:6b8:b000:605c:e61d:2dff:fe03:3790 [ 30.898569] netpoll: netconsole: remote ethernet address b0:a8:6e:f4:ff:c0 [ 30.917747] console [netcon0] enabled [ 30.917749] netconsole: network logging started [ 31.453353] e1000e 0000:02:00.0: Some CPU C-states have been disabled in order to enable jumbo frames [ 34.185730] e1000e 0000:02:00.0: Some CPU C-states have been disabled in order to enable jumbo frames [ 34.321840] e1000e 0000:02:00.0: Some CPU C-states have been disabled in order to enable jumbo frames [ 34.465822] e1000e 0000:02:00.0: Some CPU C-states have been disabled in order to enable jumbo frames [ 34.597423] e1000e 0000:02:00.0: Some CPU C-states have been disabled in order to enable jumbo frames [ 34.745417] e1000e 0000:02:00.0: Some CPU C-states have been disabled in order to enable jumbo frames [ 34.877356] e1000e 0000:02:00.0: Some CPU C-states have been disabled in order to enable jumbo frames [ 35.005441] e1000e 0000:02:00.0: Some CPU C-states have been disabled in order to enable jumbo frames [ 35.157376] e1000e 0000:02:00.0: Some CPU C-states have been disabled in order to enable jumbo frames [ 35.289362] e1000e 0000:02:00.0: Some CPU C-states have been disabled in order to enable jumbo frames [ 35.417441] e1000e 0000:02:00.0: Some CPU C-states have been disabled in order to enable jumbo frames [ 37.790342] e1000e: eth1 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None This patch flushes tx buffers only once when carrier is off rather than at each watchdog iteration. Signed-off-by: Konstantin Khlebnikov <redacted>
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 189f231075c2..d10083beec83 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c@@ -5309,8 +5309,13 @@ static void e1000_watchdog_task(struct work_struct *work) /* 8000ES2LAN requires a Rx packet buffer work-around * on link down event; reset the controller to flush * the Rx packet buffer. + * + * If the link is lost the controller stops DMA, but + * if there is queued Tx work it cannot be done. So + * reset the controller to flush the Tx packet buffers. */ - if (adapter->flags & FLAG_RX_NEEDS_RESTART) + if ((adapter->flags & FLAG_RX_NEEDS_RESTART) || + e1000_desc_unused(tx_ring) + 1 < tx_ring->count) adapter->flags |= FLAG_RESTART_NOW; else pm_schedule_suspend(netdev->dev.parent,
@@ -5333,14 +5338,6 @@ static void e1000_watchdog_task(struct work_struct *work) adapter->gotc_old = adapter->stats.gotc; spin_unlock(&adapter->stats64_lock); - /* If the link is lost the controller stops DMA, but - * if there is queued Tx work it cannot be done. So - * reset the controller to flush the Tx packet buffers. - */ - if (!netif_carrier_ok(netdev) && - (e1000_desc_unused(tx_ring) + 1 < tx_ring->count)) - adapter->flags |= FLAG_RESTART_NOW; - /* If reset is necessary, do it outside of interrupt context. */ if (adapter->flags & FLAG_RESTART_NOW) { schedule_work(&adapter->reset_task);